Heat radiator



M. UNGER HEAT RADIATOR Filed Nov;

Inventor: Magnus Un ger,

His Attorney.

, I?! z I /Illllllllllrll Patented Jan. 31, 1933 UNITED STATES.

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PATENT OFFICE PITTS IIELD, IASSACHUSETTS, ASSIGNOB TO GENERAL ELECTRICCOKPAKY, A CORPORATION OF NEW YORK rma'r nama'roa Application filedNovember 11 193 'Seflal 110. 574,388.

My invention relates to heat radiators and more'particularly to the typeof heat radiator having top and bottom headers connected by tubes. Inthe-production of radiators of this type, it'has been customary to makethe headers of sheet metal with flanged openings into. which the ends ofthe tubes are welded. The general object of the invention-isto'prov'idexan improved radiator of this type. a I

The objects and advantages of the invention will be apparent fromthe-following description taken in connection with the accompanyingdrawing in' which Fig. 1 is a side'view of a radiator constructedinaccordance with the invention and connected to the casing of atransformer for cooling a body of liquid in which the transformer isimmersed, and Fig. 2 is an enlarged sectional view on the line 2-2 ofFig. 1 of one side of the radiator with the central parts of the tubesbroken away.

Like reference characters indicate similar parts in both figures of thedrawing.

The radiator shown in the drawing has a top header 10 and bottom header11 connected by metal tubes 12. The headerslO and 11 are formed of sheetmetal with openings having flanged edges 13 into which the ends of thetubes are inserted and welded.

,In Fig. 1, the headers are shown connected is immersed in an insulatingliquid 16. As

the liquid about the transformer is heated, it rises by convection,flows into the top header 10, down through the tubes 12 where it iscooled, and finally returns through the bottom header 11 to thetransformer casing ready to absorb more heat from the transformer. t

The purpose of the radiator is to transfer heat from the liquid insidethe tubes to the air surrounding the tubes and in the spaces betweenthem. In order to do this most efiiciently, the walls of the tubesshould be as, thin as possible and still have the necessary mechanicalstrength and the air around and between the tubes should be free to riseby convection along the surfaces of the tubes with the least possibleobstruction. If simple,

straight tubes with very thin walls are used, however, it is 'not easyto weld the ends of the tubes into the headers without burning throughthe thin tube walls. If more than one row of'tubes is used as indicatedin the drawing, the air that flows up between the tubes cannot flowthrough the .radiator headers but must flow in-between the lower ends ofthe tubes and out between the up er ends of the tubes. If simplestraight tuhes are spaced far enough apart so that they do not interferewith this flow of air between them, the radiator is unduly bulky and ifthe tubes are spaced closely together to make the radiator compact theair cannot flow freely into and out of the spaces between the tubes. Theinvention avoids all these difficulties by using jointless thin walledtubes 12 with their ends 17 swaged to reduce their diameters. Theswaging process not only reduces the diameters of the ends of the tubesbut increases the thickness of the walls of the tube ends so that theymay be welded easily into the headers without danger of burning throughthe tubes. The swaging process also increases the spacing between theends of the tubes so that the intermediate portions of the tubes may bespaced'very closely together and still the air can flow readily 'in andout between their ends. The increased spacing of the ends of the tubesdue to the swagin of the tube ends also makes the welded oints betweenthe tubes and headers more readil accessible for the repair of anyleakswhich may develop in these joints.

The invention has been explained by describing and illustrating aparticular radiator constructed in accordance with the inven-tion, butit will be ap arent that changes may be .made without departing from thespirit of the invention or the scope of the Y said headers, the tubeshaving ends of greater wall thickness than the intermediate portions ofthe tubes, and said tube ends extending into said flanges and beinwelded thereto. a

2. A heat radiator inclu ing top and bottom headershaving openingssurrounded by" 5 external flanges and trreta l tubes connecting saidheaders thetubs having ends of smaller diameter and greater wallthickness than the intermediate portions of the tubes, and 7 said tubeends extending into said flanges and 10 being welded thereto. I

' In witness whereof, I have hereunto set my hand.

-MAGNU S UNGER.

